Monolithic Active Pixel Sensors (MAPS) in advanced CMOS nodes must balance timing, power, and noise for next-generation tracking detectors. For the CEPC Inner Tracker, the system-level requirements are a timing resolution of ~3 ns and power consumption below 150 mW/cm². Within this power budget, the analog front-end (AFE) consumes the largest fraction, making its optimization the most...
This paper presents the implementation and open-loop validation of a cavity emulator for the 1.3 GHz pulsed superconducting-cavity LLRF system under development in our group, for which the real cavity will not be available for an extended period. The emulator runs on an AMC-7Z045 board (Xilinx XC7Z045) and executes the cavity, RF-amplifier, coupler, beam, and detuning models as a pipelined...
This study evaluates the Accelerator Physics Emulation Studio (APES) against the Strategic Accelerator Design (SAD) code for simulating single beam background processes at BEPCII‑U, with a focus on physical modeling and computational performance. In terms of physics, APES shows good agreement with SAD in scattering generation, optical functions, beam lifetimes, and loss distributions near the...
High-power klystrons play a critical role in microwave power amplification in radio-frequency (RF) systems for large-scale accelerators, and their operational stability directly affects the long-term reliability of the RF system. To investigate output-power fluctuations, electron reflection, and parasitic oscillations that may occur under load-mismatch conditions, this study takes the output...
This work presents the design and analytical optimization of a high-power, high-efficiency S-band multi-beam klystron (MBK) intended as an RF power source for large-scale scientific facilities. Existing accelerator klystrons demonstrate $50-80 MW$-class peak power near $2.856 GHz$, whereas established MBKs and recent high-efficiency developments operate in the $60-70\%$ electronic-efficiency...
High-efficiency klystrons can significantly reduce the operational costs of particle accelerators. For the low-duty-factor klystrons commonly used in linear accelerators, however, the power consumption of electromagnetic focusing coils remains non-negligible. This work presents the progress of an S-band 50 MW high-efficiency klystron with periodic permanent magnet (PPM) focusing, aiming at...
Silicon microstrip detectors provide high spatial resolution, reliable charge measurement, and a scalable detector architecture, making them well suited for charged-particle tracking, beam monitoring, and detector prototyping. In this work, we present the development and initial characterization of a compact silicon microstrip tracking system based on p-on-n strip sensors. Each detector module...
The reliable operation of high-power RF components, such as input couplers and RF windows, is critical for the Circular Electron Positron Collider (CEPC) project. Prior to installation into the accelerator system, these components require rigorous high-power conditioning to verify their RF performance and thermal stability. However, establishing megawatt-level test facilities is challenging...
Particle magnetic spectrometers are essential instruments in particle physics, enabling precise measurements of the momentum, charge, time of flight, and energy of charged particles. Driven by the requirements of next-generation magnetic spectrometer experiments, the project team focuses on key technologies for high-precision semiconductor tracking detectors. The project advances the...
For large particle accelerators, the radio-frequency (RF) power source system accounts for a significant portion of total energy consumption. A considerable fraction of the RF power that is not used for particle acceleration is delivered to an absorbing load located at the output of the accelerating structure, where it is converted into heat and dissipated. Recovering this otherwise wasted...
High-voltage pulse modulator is a key device in linear accelerators, serving as the intermediate link that converts power from the power supply into microwave power. According to the CEPC technical design, the linear accelerator requires 236 sets of C-band 80 MW power source systems to supply 5712 MHz/3 μs/100 Hz pulsed power to the accelerating structures. To achieve the target klystron...
The increasing level of front-end integration in particle detector has placed new requirements for powering system, particularly in terms of material budget, power distribution, and system scalability. Serial powering, based on a constant current scheme with shunt-LDO regulars (SLDO), has been an attractive solution for large-scale detector systems and future collider upgrades.
This...
The operating voltage of high‑power klystron electron guns reaches the hundred‑kilovolt level. High electric‑field gradient inside the gun readily causes vacuum breakdown and other adverse phenomena, which degrade the voltage withstand capability and service life of the device. Taking a high‑efficiency klystron electron gun as the research object, this paper adopts the Non‑dominated Sorting...
Accurate simulation of beam-beam interaction backgrounds, particularly the copious production of incoherent electron-positron pairs, is essential for detector design and physics analysis at the future Circular Electron Positron Collider (CEPC). However, the high computational cost of established codes such as Guinea-Pig++ presents a bottleneck for generating the large-statistics datasets...
COFFEE3 is a 55 nm HV-CMOS pixel detector prototype developed for the CEPC inner tracker. Following previous bench tests with charge injection, laser illumination, and a 55Fe source, two beam-test campaigns were carried out at the CERN SPS in May and July 2026. Clear responses to high-energy charged particles are observed, together with temporal correlation with scintillator reference signals....
A resistive heating film was developed to simulate pixel sensor and readout heat loads in the innermost layer of the vertex detector. To simplify signal routing outside the cooling chamber, two sensing configurations were designed: a flexible printed circuit (FPC) carrying 11 surface-mount PT100 sensors, and individually wired PT100 probes (manually assembled using enameled Cu wire and UV...
Accurate jet energy reconstruction is essential for precision studies of hadronic Higgs, W, and Z boson decays at the Circular Electron Positron Collider (CEPC). The CEPC Reference Detector Technical Design Report reports a baseline jet energy resolution of approximately 4.5–5.0% for light-quark jets in the barrel region. Building on this benchmark, this study explores machine learning to...
Future electron-positron colliders, such as CEPC, FCC-ee, and ILC, are being proposed for precision studies of the Higgs boson, electroweak physics, and flavor physics. These ambitious physics programs require excellent particle identification (PID) over a wide momentum range. The Time Projection Chamber (TPC), with its low material budget and excellent tracking capabilities, is the baseline...
The BEPCII Upgrade (BEPCII-UP) adopts the crab waist collision scheme to significantly enhance luminosity. In this study, lattice design (including the survey, optics parameters, and working point matching) and dynamic aperture optimization for the BEPCII-UP collider ring are carried out using the SAD code. To obtain a sufficient dynamic aperture for injection, a combined-function magnet...
Utilizing advanced 55 nm HVCMOS technology, the Inner Tracker (ITK) is a key component of the AGORA detector tracking system, originally proposed for the CEPC. The ITK features a highly modular design, with each basic module integrating up to 14 sensor chips. Pending the availability of full-size chips, prototyping efforts have commenced with dummy sensors that replicate the geometric...
This work presents the design and multi-code simulation of a 10 MW-class L-band (1.3 GHz) multi-beam klystron (MBK) intended as a high-efficiency RF power source for superconducting linear accelerators. The design covers the electron gun, magnetic focusing system, RF interaction structure, output window, and collector. Six low-perveance (0.57 μP) beamlets extracted at a cathode voltage of...
We present a neural-network-based method for transverse position reconstruction in strip AC-LGADs for future collider applications. Laser scans of a four-strip sensor with different inter-electrode gaps and signal intensities are used to study the reconstruction performance. Neural-network approaches are compared with conventional amplitude-based methods, with particular attention to spatial...
CEPC mechanical-stability studies specify stringent ground-motion requirements, with RMS displacement integrated over 1-100 Hz of ≤4 nm for the machine-detector interface (MDI) and ≤24 nm for the collider arc, straight and RF sections. In addition to ground-borne vibration, cooling-water systems can act as a direct source of mechanical excitation in accelerator magnet systems. Previous in situ...
High-voltage CMOS (HV-CMOS) pixel sensors represent a promising candidate for tracking applications in future high-energy physics experiments. Building upon the established 180 nm and 130 nm process nodes, our COFFEE2 prototype has been developed in a commercial 55 nm HV-CMOS technology to further explore the performance potential of advanced CMOS processes. The COFFEE2 chip integrates not...
Layout design is a core procedure in particle accelerator development, which guarantees the precise implementation of physics design and underpins full-lifecycle operation and maintenance of the facilities. 2D layout drawings act as fundamental engineering benchmarks for equipment positioning, while 3D layout models provide a global spatial perspective for coordination verification and...
The storage ring vacuum system is a core component ensuring stable beam operation. Its primary function is to provide an ultra‑high‑vacuum environment with ultra‑low gas density for the beam, mitigate scattering losses induced by interactions between the beam and residual gas, and prolong beam lifetime.
The storage ring vacuum system mainly consists of Cr‑Zr‑Cu vacuum chambers,...
Quantum-information observables offer new tools for probing collider events beyond traditional quantities such as cross sections and invariant masses. This work investigates quantum entanglement in top–antitop pairs produced via e⁺e⁻ → tt̄, using spin density matrices generated with the recently developed Density Mode framework within MadGraph5_aMC@NLO. Events were simulated at leading order...
Accurate modelling of charge sharing and pixel response is essential for evaluating the performance of the Circular Electron–Positron Collider (CEPC) vertex detector, particularly for tracks at large incident angles. We present an Allpix²-based simulation and digitization workflow for TaichuPix monolithic active pixel sensors developed for CEPC, with an emphasis on the processes connecting...
Modern detector systems for particle physics, such as the outer tracker (OTK) of the future CEPC detector, aim to simultaneously improve timing and spatial resolution while reducing the amount of material in the detector and simplifying its readout electronics. One possible solution is the use of RSD-LGAD sensor strips with lengths on the order of centimeters. Such sensors can provide particle...
Flavor physics and jet measurements at the Circular Electron Positron Collider (CEPC) impose stringent requirements on particle identification (PID). The drift chamber is a key candidate for the tracker, and primary ionization cluster counting (dN/dx) offers superior PID by resolving individual ionization clusters. Simulations indicate that an optimized dN/dx drift chamber can achieve K/π...
Conventional semiconductor-based energy-dispersive spectrometers offer high detection efficiency but relatively limited energy resolution, whereas crystal-based wavelength-dispersive spectrometers can achieve excellent energy resolution at the cost of collection efficiency and simultaneous spectral coverage. Transition-edge sensor (TES) microcalorimeters can combine high energy resolution,...
A drift chamber(DC)-based design has been chosen and done as a possible alternative to the TPC, in order to contribute its PID performance in the CEPC reference detector’s design [1].
One hand is to study and optimize the resolution of d𝑁/d𝑥 with the advanced electronics and the multilayer DC prototype .Thanks to the nice collaboration with the Italian group, after the study of the simulation...
UP bare stave design and thermal study
